More than half of all criminals ordered to wear an electronic tag break their curfews, official figures show.

Many criminals with electronic tags are still defying their curfews, figures show (Picture: Alamy)

Some 59 per cent of offenders ordered to be tagged by courts receive at least a warning, an analysis of more than 80 cases by Her Majesty’s Inspectorate of Probation found.

If the trend is correct it means at least 47,000 of them transgress at least once. More than a third were sent back to court following serious violations.

The most worrying finding was that, in a fifth of cases where there were violations, inspectors could not even see who was supposed to be in charge, said chief inspector Liz Calderbank.

Offenders could break the terms of their curfew for up to two hours before getting a warning and for four hours on many occasions before court action was considered.

Inspectors also found court paperwork was unclear, illegible or wrong, leading to delays in enforcement. Action had to be stopped once it emerged that the person who thought they were responsible had no legal authority.

Plans to extend the use of tagging were set out by justice secretary Kenneth Clarke in March. Their use by courts has already more than doubled in the last six years, with 80,000 offenders being tagged in 2010-11.

That included 65,000 by courts and 15,000 who were released early from prison, costing some £100million. Despite that, the system is cheaper than the £45,000 annual cost of a prison place.

‘The danger is that the tagging is used as a one-size-fits-all approach,’ said Andrew Neilson of the Howard League for Penal Reform.

‘We are concerned at the danger of over-relying on technology at the expense of tailored support with staff contact and interventions.’